1. Field of the Invention
This invention is directed to apparatus for evacuating containers and more specifically to an appliance that facilitates the storage of foodstuffs or other articles in a sealed, evacuated container.
2. Description of Related Art
Many times there is a need to store articles, particularly perishable foods, for prolonged intervals. Such prolonged storage can be enhanced if the articles are in an environment that will preserve those articles. For example, it is often desirable to store foodstuffs in a sealed, evacuated container to reduce any interaction between the stored foodstuffs and oxygen and humidity thereby to prevent food spoilage. Such evacuated environments can also prevent other materials from deteriorating.
A wide variety of commercial and domestic apparatus for evacuating rigid and flexible containers exists. Commercial apparatus, however, tends to be physically large, complicated to use and expensive and therefore unsuited to home use. For example, U.S. Pat. No. 1,967,346 (1932) to Barnby discloses apparatus for vacuumizing and sealing containers. This patent discloses a chamber for receiving large numbers of containers and various components that are required to implement container sealing in such large chambers.
Similarly, U.S. Pat. No. 4,154,044 (1979) to Lang discloses an apparatus for sealing cans with lids under vacuum. This apparatus uses a lifting device and a vacuum bell. An unsealed container is placed under the vacuum bell. A vacuum is drawn and evacuates the container while the lid is spaced from the container. Once an appropriate vacuum exists, the lifting device raises the container and presses the lid in place. Then the vacuum bell can be brought to atmospheric pressure and the sealed container can be removed.
U.S. Pat. No. 5,056,292 (1991) to Natterer discloses a packaging machine with a vacuum chamber divided into lower and upper chamber parts. The upper chamber part is movable relative to the lower chamber part. In use articles are placed in a bag in the upper chamber part that then is brought into sealing relationship with the lower chamber part. A vacuum pump evacuates the chamber parts. When the vacuum reaches a prescribed level, sealing bars in the upper chamber part seal the bag. Then air under atmospheric pressure enters the chamber.
As previously stated, apparatus such as that described above are too complicated, unwieldy and costly for household use. Consequently a wide variety of processes and appliances for providing evacuated storage have evolved. The most basic process involves placing an open container with its contents in a boiling water to heat the contents and expand the gas in the container. After the appropriate temperature has been reached, a lid seals the container opening and the container is removed. As the container and contents cool and as the container now has a constant gas volume, the gas pressure reduces to provide vacuum sealing.
In accordance with another approach, flexible bags are evacuated to collapse around articles whereby the bag closely conforms to the articles. For example, U.S. Pat. No. 4,478,025 (1984) to Scanlan discloses a packing device for vacuum sealing perishable materials in bags. A loosely positioned clamp means is placed about the open end of the bag that is filled with foodstuffs or the like. The bag and clamp are placed in a vacuum chamber. As a vacuum is drawn, the bag compresses around the articles and the clamp seals the bag.
U.S. Pat. No. 5,239,808 (1993) to Wells et al. discloses a vacuum packaging machine with a chamber and lid movable between an open position exposing the chamber and a closed position sealing the chamber. The chamber contains a seal bar. In use, the bag and its contents are positioned in the chamber and in the seal bar. A vacuum is drawn to evacuate any air from the bag and collapse the bag closely to the contents. Then the sealing bar forms a seal across the container opening.
U.S. Pat. No. 5,528,880 (1996) to Landolt discloses an apparatus for performing a similar operation utilizing a machine with a vacuum chamber and a number of automatically operated valves and a vacuum sensor. An evacuation operation continues until a predetermined vacuum has been drawn within the chamber. Then another valve opens to atmospheric pressure to complete the sealing operation.
U.S. Pat. No. 5,628,404 (1997) to Hendrix discloses a portable self-contained vacuum packing device with an outer flexible container, two one-way valves and an inner flexible container. Squeezing the outer container compresses the air and causes the flexible inner container to conform to the contents. Air escapes through one of the one-way valves that blocks the return of air into the compressed inner container or package.
In a more mechanized approach particularly adapted for rigid containers, vacuum sealing devices include platforms, bell covers or jars for providing evacuation chambers and manual pumps for evacuating containers with lids. For example, U.S. Pat. No. 1,594,512 (1924) to Von der Lippe-Lipski discloses an apparatus for preserving food in which a container with a loose fitting top is placed in an evacuation chamber. The chamber is evacuated with a manual pump thereby reducing the pressure within the container as air passes from the container past the loose fitting lid. Then atmospheric air is admitted to close the lids on the food jars and hermetically seal the contents.
U.S. Pat. No. 4,372,096 (1983) to Baum discloses a vacuum sealing device that generates a vacuum in the head space of a jar by means of a hood connected to an external vacuum pump. A valve assures that air under atmospheric pressure can not enter the hood until the lid has been pressed against the top edge of the jar""s mouth.
U.S. Pat. No. 4,909,014 (1990) to Kobayshi et al. discloses a vacuum storage device with a base member, a housing sealingly and removably mounted on the base member to form a storage chamber, a pressure reducing device mounted on either of the base member and housing member and a means for introducing air into the storage chamber. In this disclosure a bell and bellows pump with a valve provides a method of reducing the air pressure within the storage chamber. After predetermined pressure reduction has been achieved, another valve admits air at atmospheric pressure into the storage chamber thereby to seal a lid to a container.
Each of these devices provide evacuated containers utilizing a fully manual operation. Moreover the apparatus tends to be overly complicated and involves entirely manual control. More recently, however, a vacuum sealing appliance for home use has been presented that utilizes an electric vacuum pump, a valve and control system that simplifies the sealing of a lidded container. More specifically, U.S. Pat. No. 6,012,265 (2000) to Ady discloses a portable vacuum apparatus with a vacuum chamber for lidded jars and the like. The vacuum chamber comprises a platform covered by a layer of resilient materials serving as a seal and a removable cover seated on the platform. Piping connects the vacuum chamber to an electrically operated vacuum pump and to an automatic valve that can connect the chamber with the atmosphere. To evacuate a jar or container in the chamber, the valve is manually closed to start pumping thereby exhausting air from the chamber and the jars. When the required vacuum has been reached, the valve opens automatically and interrupts the electrical supply to the vacuum pump. The valve also forms a wide passageway to the chamber causing air to rush in and create a shockwave. The lids on the jars and containers are conventional and have gaskets that are slightly lifted off the seats during evacuation. The shockwave firmly presses the lids onto the containers and closes the container under a vacuum condition.
More specifically, as the vacuum increases, a pressure differential exists across a sliding valve member held in position by a restraining mechanism. When the differential pressure across the valve, produced by the reduced pressure and atmospheric pressure on the opposite sides of the valve, becomes sufficiently great, the restraining force provided by the detent is overcome. The valve slides to the open position. In one embodiment the restraining mechanism comprises a mechanical detent; in another, by a permanent magnet. It has been found that this valve can not guarantee a release at a constant vacuum with either a mechanical or magnet restraining mechanism. Both restraining mechanisms are dependent upon environmental effects, machine tolerances, wear and tear and other factors for determining their release points. Consequently the vacuum at which air is admitted can vary from apparatus to apparatus and, within a given apparatus, over time. Moreover, the device shown can be applied only with a bell jar. However, it is often desirable to evacuate containers that are larger than the bell jar. The Ady patent does not disclose any method for evacuating such lidded containers. What is needed is a low-cost reliable vacuum sealing appliance for lidded containers that is easy to use and adapted for home use.
Therefore it is an object of this invention to provide an improved appliance for evacuating lidded containers.
Another object of this invention is to provide an improved appliance for evacuating lidded containers in a non-commercial or home environment.
Still another object of this invention is to provide an improved appliance for evacuating lidded containers that is simple to operate.
Yet another object of this invention is to provide an improved appliance for evacuating lidded containers that can be manufactured at reasonable costs.
Yet still another object of this invention is to provide an improved appliance for evacuating lidded containers both in a bell jar on the appliance and containers that are remote from the appliance.
In accordance with one objective of this invention, a vacuum sealer for sealing the contents of a lidded container includes a vacuum pump and a vacuum chamber that receives the container with a loosely positioned lid. A controller contains a valve operable between sealed and unsealed positions and a vacuum switch. Operation begins by moving the valve to its sealed position thereby activating the vacuum pump to evacuate air from the container and the vacuum chamber. When the vacuum switch indicates a predetermined vacuum, the valve is permitted to return to its unsealed position allowing air at atmospheric pressure to rush into the vacuum chamber and seal the lid against the container and turning off the vacuum pump.
In accordance with another aspect of this invention, a system for vacuum sealing a container includes a housing with first and second internal cavities separated by a wall. First and second ports extend through the wall. A vacuum pump and control system are located in the first cavity. A vacuum chamber base also attaches to the housing. A first vacuum hose extends between the first port and the vacuum pump and a second vacuum hose extends between the second port and the vacuum chamber base. A third vacuum hose in the second cavity connects to the first port and releasably connects to the second port. The third vacuum hose and second port have complementary fittings to form a releasable interconnection. For remote operations a lid is placed on an open container separated from the vacuum chamber base. The third vacuum hose then attaches to a vacuum fitting corresponding to the second port fitting. Thereafter, energizing the vacuum pump evacuates the container under the lid.